Basic Investigation of Fe-Pt Magnetic Alloys to Crown and Bridge Prosthodontics.

我们已经设计和研究了新的可移动冠和桥。牙冠和牙桥分别用Fe-Pt-Nb磁性合金外盖和磁性不锈钢内盖进行牙铸造，使磁力增强其物理强度。本研究的目的是研究Fe-Pt-Nb磁性合金在牙科铸造外盖上的适用性。第一个实验是研究钛投资和模具温度的差异对Fe-Pt-Nb磁性合金的影响。第二个实验是研究添加元素Si和Nb对Fe-Pt-Nb磁性合金的影响。最后研究了不同磁化方式对Fe-Pt-Nb磁性合金中引力的影响。实验结果如下：1.实验结果表明：通过对表面韧性和磁性能的测试，确定了Fe-Pt-Nb磁性合金牙用铸造的最佳工艺条件为钛合金熔量（Titavest CB）和模温（200-600℃）。添加0.1（摩尔%）以上的Si可以改善表面粗糙度，减少铸造缺陷，添加0.2（摩尔%）以下的Si和0.5（摩尔%）以上的Nb可以产生优异的磁性能。因此，优选出Fe-39.5Pt-0.65Nb-0.1Si（摩尔%）。王冠型（沿王冠轴磁化）Fe-39.5Pt-0.65Nb-0.1Si（摩尔%）的引力平均为536gf。这个值足以保留可移动的牙冠和新娘用于牙科。这些合金的自适应精度与吸引力和力学性能之间的关系有待进一步研究。

We have designed and studied new removable crowns and bridges. The crowns and bridges are separately prepared by dental casting with Fe-Pt-Nb magnetic alloys for outer caps and magnetic stainless steel for inner caps, respectively, so that magnetic force reinforce their physical strengh. The purpose of this study was to examine the applicability of Fe-Pt-Nb magnetic alloys to outer caps by dental casting. The first experimentation was to investigate effects of differences in titanium investments and the mold temperature on Fe-Pt-Nb magnetic alloys. The second experimentation was to investigate effects of additive elements such as Si and Nb on Fe-Pt-Nb magnetic alloys. The last experimentation was to investigate effects of magnetizing nethods on attractive forces in Fe-Pt-Nb magnetic alloys. The results were as follows :1.Measuring surface foughness and magnetic properties, titanium investment (Titavest CB) and the mold Temperature (200-600ﾟC) were optimum condition for dental casting of Fe-Pt-Nb magnetic alloys.2.The addition of Si 0.1 (mole%) over improved the surface roughness and decreased the casting defect, and the addition of Si 0.2 (mole%) below and of Nb 0.5 (mole%) over could produce the excellent magnetic properties. Therefore, it was conducted that the optimal composhition was Fe-39.5Pt-0.65Nb-0.1Si (mole%).3.The attractive force which was observed with crown-type (magnetized along the crown axis, Fe-39.5Pt-0.65Nb-0.1Si (mole%)) showed 536gf on the average. This value is enough to retain removable crowns and brides for dental use.Further study is needed to elucidate the relationship between the adaptation accuracy and the attractive force as well as mechanical properties of these alloys.